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Try some basic stuff first. Using a voltmeter, ensure that the voltage at the terminal on the breakout board goes from +5 (when the switch is not activated) to 0 (when the switch is activated.) If this is not the case:
Is the common wire ( the one that goes to all switches) connected back to ground on the "correct" side of the breakout board?
Are the switches wired properly (e.g., in parallel pairs for X and Y) for your chosen approach to limit switches?

I am just finishing my build of my first CNC machine (a Fireball V90,) so I have very recent experience of making a bunch of mistakes.


There are (at least) four approaches to limit switches:
1) wire each switch to a pin
2) wire the two switches on an axis to the same pin (3 pins total)
3) wire high limits to one pin and low limits to another pin (2 pins total)
4) wire all limit switches together to one pin.

I used the simple (number 4) approach. Which one are you using?